1. Field of Invention
The invention pertains to looms wherein fabric as it is formed is incrementally advanced by a take-up roll that is rotated by the combination of a ratchet wheel operatively associated with one end thereof and so-called feed and hold-back pawls which are mounted so as to engage the teeth of said ratchet wheel.
2. Description of the Prior Art
In looms for weaving it is customary to provide a knockoff means which serves to initiate stopping of the looms preferably by disconnecting the source of power and applying a brake to accelerate the stopping function. Such mechanism is normally dependent upon or functions in accordance with indications taken from a weft feeling or sensing mechanism, such as in and of itself, well known to those conversant in the weaving art.
When a loom stops as a result of weft breakage, the loom is turned over to that shed opening containing the broken weft, and during this turning over of the loom, the reed is caused to strike the fell line of the fabric. The reed's striking of the fell during this turning over of the loom has a tendency to pack the preceeding length of weft more tightly than those which form the fabric immediately adjacent thereto or which precede said length of weft. This additional beat-up or packing of the weft also has a tendency to stretch slightly the warp threads at this point and together form a distinct line or, in other words, a starting mark when the loom is started in order to resume weaving.
A number of prior art patents disclose devices for preventing start marks in fabric and for a more detailed description of these devices, attention is directed to U.S. Pat. Nos. 3,165,125 and 3,891,010.
When a loom stops as a result of a weft break, the start mark preventer of the present invention is adapted to be pre-set so that the fell can be moved forwardly of the reed beat-up position a pre-selected distance to meet the requirements of a particular type of fabric when the loom is turned over to the shed opening containing the broken pick. After removal of the broken pick of weft, the device is again actuated and the fell is caused to return to the precise position whereat weaving can be resumed without creating a start mark in the fabric.